1. Field
The present disclosure relates generally to modifying sound. The present disclosure relates specifically to materials including individual cells which act together to modify sound waves.
2. Background
Modification of sound is desirable in many circumstances, such as reducing sound by using headphones that cancel surrounding noise. Devices for use in larger applications, for example on aircraft and other vehicles to reduce or redirect sound have many useful military and commercial applications.
Passive techniques for reducing the noise in aircraft and other vehicles are known. For example, vehicle structures may be provided with passive foams, beads, acoustic blankets, or other materials to absorb sound energy. However, such devices typically add considerable undesired weight and are not able to regulate the amount of sound transmitted or received. Active noise cancellation techniques, such as the headphones described above, are not practical for use with large structures, such as aircraft and vehicles. Thus, methods and devices for modifying the amount of sound made by vehicles and other devices using only lightweight and strong materials are desirable.